“As the anomalies tend to occur only during relatively long-duration events, it is not only the peak intensity of the electron flux but also the duration of the exposure that determines the amount of excess charge accumulation.” https://t.co/O218eVjrnc
“The discharges can produce short-lived (fractions of a microsecond) but intense (several Amperes) current pulses.” https://t.co/O218eVjrnc
“The excess negative charge can give rise to potential differences, which in turn can lead to intense voltage discharges and surges of electric energy deep inside the electric circuits of the spacecraft causing severe damage to various subsystems.” https:/
High energy space junk. “High-energy electrons in the outer Van Allen radiation belts can penetrate through spacecraft walls and through electronics boxes and become buried in dielectric materials.” https://t.co/O218eVjrnc
Solar energetic particles. “Single event upsets are commonly detected in transistors and spacecraft memory devices. Error-correcting software solutions have been developed to decrease the damages to the satellite operations.” https://t.co/O218eVjrnc
RT @TenFleming: Solar energetic particles. “Single event upsets can occur in electronic components when a charged particle (e.g., a heavy i…
Solar energetic particles. “Single event upsets can occur in electronic components when a charged particle (e.g., a heavy ion) ionizes a track along a sensitive part of the circuit and causes the circuit to change state.” https://t.co/O218eVjrnc
“Solar energetic particles arising from active events on the Sun cause degradation and failure of space-borne systems.” https://t.co/O218eVjrnc
“The high energies above tens of MeV make galactic cosmic rays highly penetrating into the satellite systems, where they can cause a wide variety of harmful effects.” https://t.co/O218eVjrnc
The South Atlantic Anomaly region “where the Earth’s magnetic field is weakest and the energetic particles thus have best access to altitudes where the low-Earth-orbiting spacecraft reside (∼ 300–1000km altitude).” https://t.co/O218eVjrnc
“While malfunctions such as memory upsets can occur almost anywhere, a vast majority of the events are observed in the southern hemisphere over the South Atlantic Anomaly region.” https://t.co/O218eVjrnc
“High-energy ions trapped in the Earth’s magnetic field can cause significant effects in spacecraft systems.” https://t.co/O218eVjrnc
The things that can happen, “Illustration of the chain of events from the Sun to the Earth related to ground-based space weather effects.” You have to see this one. https://t.co/O218eVjrnc
Electromagnetic disturbances and bombardment by energetic electrons and ions: “understanding these processes is important both for the design and maintenance of these systems.” https://t.co/O218eVjrnc
“Our lives have become increasingly dependent on technological systems that are vulnerable to electromagnetic disturbances and bombardment by energetic electrons and ions.” https://t.co/O218eVjrnc
“The dynamic processes associated with the solar wind-magnetosphere-ionosphere coupling processes can have significant effects in the near-Earth space environment, in the atmosphere, and on the Earth’s surface.” https://t.co/O218eVjrnc
“It seems that resolving their temporal evolution requires detailed knowledge of the dynamics and coupling of as well the cold plasmasphere, hot ring current, tail plasma sheet as the electromagnetic fields guiding the particle motions.” https://t.co/O218e
“The relativistic electrons themselves interact relatively weakly with the other plasma populations.” https://t.co/O218eVjrnc
“The substorm-associated energetic electrons can act as a seed population that, if further energized, can become part of the outer van Allen belt relativistic electron population.” https://t.co/O218eVjrnc
“The rapid field variations provide a means for pitch-angle scattering as well as inward transport and adiabatic energization of the electrons.” https://t.co/O218eVjrnc
“Substorms are associated with inductive, localized electric fields, and are effective in transporting both electrons and ions to the inner magnetosphere.” https://t.co/O218eVjrnc
“As these wave modes are key elements for both acceleration and loss of the relativistic electrons, the plasmasphere and its dynamics driven by the large-scale convection electric field play a key role in the relativistic electron problem.” https://t.co/O2
Changes in the convection electric field “thus changing the locations where the plasmaspheric hiss...EMIC waves (in the dusk sector, inside the plasmapause), and whistler mode chorus waves (in the morning sector, outside the plasmapause) occur.” https://t.
“Changes in the large-scale convection electric field change the plasmaspheric configuration.” https://t.co/O218eVjrnc
Mix in some space weather. I dunno, seems plausible.
Everything connects. “The ring current ions affect the relativistic electron population through their influence on the field configuration and through their influence on wave development.” https://t.co/O218eVjrnc
The magnetic field configuration “is determined by the large-scale current systems, in the inner magnetosphere mainly the ring current carried by energetic ions.” https://t.co/O218eVjrnc
“The magnetic field configuration is a key element in determining the adiabatic transport properties of both electrons and ions.” https://t.co/O218eVjrnc
Sonic resonance. “Again, it is likely that more than one process is active in the inner magnetosphere during any given time.” https://t.co/O218eVjrnc
Sonic resonance. “Electromagnetic ion cyclotron (EMIC) waves in turn are excited near the duskside plasmapause as a result of cyclotron resonance with anisotropic ring current ions, and also interact with the van Allen belt electron population.” https://t.
“Lightning-induced whistler modes or man-made very low frequency (VLF) signals in the inner magnetosphere interact strongly with relativistic electrons.” https://t.co/O218eVjrnc
Gyroresonant. “Plasmaspheric hiss is a wave mode confined within the plasmasphere, driven unstable by gyroresonant interaction with energetic electrons.” https://t.co/O218eVjrnc
Gyroresonant. “Several wave modes interacting with the electrons at resonant energies can scatter them to the atmospheric loss cone hence leading to increased precipitation and loss of electrons from the magnetosphere.” https://t.co/O218eVjrnc
Electron losses: “convective losses by electrons drifting to the dayside magnetopause are significant especially at storm onset when the magnetosphere is often rapidly compressed to almost half of its original size.” https://t.co/O218eVjrnc
“Electron losses are similarly a combination of many processes.” https://t.co/O218eVjrnc
Processes driving magnetospheric electrons to relativistic energies: “radial diffusion, rapid transport by intense electric field pulses, and local heating via wave-particle interactions.” https://t.co/O218eVjrnc
“The candidate processes that can account for acceleration of the magnetospheric electrons to relativistic energies can be divided into three major categories.” https://t.co/O218eVjrnc
Wind driven electrons. “As southward interplanetary field and high solar wind speed are the main drivers of magnetospheric storm activity, it is not surprising that the average electron flux levels trace geomagnetic activity.” https://t.co/O218eVjrnc
Wind driven electrons. “This result was later augmented by the understanding that those high-speed streams that were coincident with southward interplanetary magnetic field were more efficient in enhancing the electron fluxes.” https://t.co/O218eVjrnc
“The relativistic electron intensity variations are driven by the solar wind and interplanetary magnetic field conditions. Early studies found a correlation between the relativistic electron flux enhancements and solar wind high speed streams.” https://t.
High fluxes of relativistic electrons. “These electrons are transported under the same electric and magnetic fields as the ring current ions, but their higher speed makes them less sensitive to the details of the electric field structure.” https://t.co/O21
“The most significant hazard to Earth-orbiting satellites is posed by high fluxes of relativistic electrons, which can penetrate the spacecraft systems.” https://t.co/O218eVjrnc
“The location of the plasmapause during storms has been shown to be a significant factor in determining the fate of the relativistic electron population in the outer van Allen belt.” https://t.co/O218eVjrnc
After the storm. “The recovery time scale is associated both with the recovery of the quiet-time electric field structure and with the outflow time scale of the cold plasma from the ionosphere.” https://t.co/O218eVjrnc
“As the storm driving subsides, the plasmasphere slowly recovers its quiet-time size.” https://t.co/O218eVjrnc
Storms. “After the field lines reconnect at the magnetopause, they convect over the polar cap toward the magnetotail, thus providing an additional source of plasma to the tail plasma sheet during storms.” https://t.co/O218eVjrnc
“During storms, the plasmapause moves inward due to the enhanced solar wind driving, while a drainage plume develops in the dusk sector. Within this plume, the cold plasma flows outward toward the magnetopause thus escaping from the plasmasphere.” https://
“During magnetic quiescence, the plasmasphere is expanded and the plasmapause can be located outside geostationary orbit. Particularly during low magnetic activity conditions, there is significant variability in the plasmapause location.” https://t.co/O218
The position of the plasmapause. “This can be understood by the enhanced convection electric field moving the boundary between the convection-dominated outer region and the co-rotation-dominated inner region closer to the Earth.” https://t.co/O218eVjrnc
“The position of the plasmapause is correlated with geomagnetic activity, being at smaller radial distances during higher levels of activity.” https://t.co/O218eVjrnc
The plasmapause. “Although roughly circular in shape, the plasmapause often shows an elongation in the duskside, following the general electric field pattern.” https://t.co/O218eVjrnc
“The location of the outer boundary of the plasmasphere, the plasmapause, is controlled by the relative intensities of the solar wind-imposed electric field and the co-rotation electric field.” https://t.co/O218eVjrnc
The plasmasphere encircling the Earth. “At low latitudes, close to the Earth, magnetic flux tubes follow drift paths that co-rotate with the Earth and therefore are filled with escaping ionospheric plasma in time scales of several days.” https://t.co/O218e
“The plasmasphere encircling the Earth is formed by cold ionospheric plasma flowing outward along magnetic field lines.” https://t.co/O218eVjrnc
“There are a number of large-scale magnetospheric magnetic field models that give the field configuration as a function of either solar wind conditions or magnetospheric activity parameters.” https://t.co/O218eVjrnc
“Substorm activity during magnetic storms causes quasiperiodic stretching-dipolarization cycles embedded within the longer-term ring current-associated changes.” https://t.co/O218eVjrnc
“In the same way, the strong ring current causes stretching of the magnetic field during magnetic storms, but in this case the changes occur over time scales of days rather than hours.” https://t.co/O218eVjrnc
Magnetic substorms “which together with the enhancing electric field causes significant changes in particle drift paths and allows for penetration of the plasma sheet plasma deep inside the inner magnetosphere.” https://t.co/O218eVjrnc
Magnetic storms. “During substorms, the intense current sheet can stretch the quasi-dipolar field lines at geostationary orbit to highly taillike ones.” https://t.co/O218eVjrnc
“Magnetic storms and substorms affect the electromagnetic field configuration in the inner magnetosphere over time scales of minutes to hours and days.” https://t.co/O218eVjrnc
“Relativistic electrons in the inner magnetosphere are a major hazard for Earth-orbiting spacecraft, and therefore prediction of the electron fluxes especially at geostationary orbit is one of the key targets for space weather applications.” https://t.co/O
The inner magnetosphere” “the hot ion ring current in the tens to hundreds of keV energy range, the outer van Allen belt electrons with energies from 100 keV up to several MeV, and the cold plasmaspheric plasma...originating from the ionosphere.” https://t
“The inner magnetosphere hosts multiple plasma populations.” https://t.co/O218eVjrnc
The inner magnetosphere “field structure caused by the competing effects of the internal dipole field, magnetotail current sheet, dayside magnetopause currents, and the ring current within the region itself.” https://t.co/O218eVjrnc
“The quasi-dipolar inner magnetosphere extending roughly out to geostationary distance has a variable field structure.” https://t.co/O218eVjrnc
Magnetosphere. “The structure and dynamics of the current sheet in the magnetotail control the energy storage and release processes initiated with the enhanced dayside reconnection at the magnetopause.” https://t.co/O218eVjrnc
“Thus, the large-scale current disruption, configuration change, and field reconfiguration all are associated with a major energy dissipation process in the magnetosphere.” https://t.co/O218eVjrnc
“The tail field reconfiguration is also associated with strong field-aligned currents to and from the ionosphere, which in part contribute to the energy dissipation in the ionosphere.” https://t.co/O218eVjrnc
“The reconnection process is associated with rapid and significant energy conversion from magnetic energy in the magnetotail lobes to particle kinetic energy and heat in the plasma sheet.” https://t.co/O218eVjrnc
“As the flows created by magnetic reconnection in the tail enter the inner magnetosphere, the large-scale magnetic field configuration changes rapidly from highly taillike to a much more quasidipolar state.” https://t.co/O218eVjrnc
“During magnetospheric substorms, a thin and intense current sheet forms in the inner part of the magnetotail as a consequence of the intensified driving.” https://t.co/O218eVjrnc
Plasma sheets. “Furthermore, complex, bifurcated current sheets and large-scale wavy structures have been identified from multi-spacecraft analyses.” https://t.co/O218eVjrnc
Plasma sheets. “The thin current sheet is often in the ion gyroradius scale, and can host very high current densities at the field reversal region.” https://t.co/O218eVjrnc
Plasma sheets. “The total current is distributed between the pre-existing thick plasma/current sheet and a newly formed thin current sheet embedded within the plasma sheet.” https://t.co/O218eVjrnc
Plasma sheets. “In the region tailward of geostationary orbit out to about 20–30 RE the changes in the current density are not uniform.” https://t.co/O218eVjrnc
“In order to maintain pressure balance between the plasma sheet plasma pressure and the lobe magnetic pressure, the cross-tail current intensifies and the plasma sheet is compressed.” https://t.co/O218eVjrnc
“As the IMF turns southward, dayside reconnection changes the conditions at the magnetospheric boundaries and begins to increase the open flux content in the magnetotail.” (IMF= interplanetary magnetic field). https://t.co/O218eVjrnc
The magnetospheric activity. “The dynamics of the cross-tail current has been intensively studied in recent years.” https://t.co/O218eVjrnc
“The magnetotail current sheet shares many of the properties of dynamically important current sheets found e.g. in the solar plasmas.” https://t.co/O218eVjrnc
“The magnetospheric activity conditions are largely controlled by the stability properties of the cross-tail current sheet.” https://t.co/O218eVjrnc
“As this is the region which feeds the inner magnetosphere with both plasma, energetic particles, and magnetic flux, the plasma sheet dynamics is crucially important for space weather applications.” https://t.co/O218eVjrnc
“While such bursts of fast flow can be observed during all magnetospheric activity conditions, they become more numerous, more intense, and have larger scale sizes during magnetically active conditions.” https://t.co/O218eVjrnc
Magnetotail plasma sheet. “These flows are most likely created by localized reconnection events initiated either by internal tail processes or by external driving conditions https://t.co/O218eVjrnc
The magnetotail plasma “during most times the net Earthward plasma flow imposed by the large-scale convection pattern is composed of short-lived (1–10 min) bursts of fast flow while the ambient plasma velocity distribution is very nearly isotropic.” https:
The magnetotail plasma sheet. “Plasma flows in this region are not laminar.” https://t.co/O218eVjrnc
“The magnetotail plasma sheet is a highly dynamic and structured region.” https://t.co/O218eVjrnc
“Space weather events are largely driven by dynamic processes that occur within the magnetotail plasma sheet separating the low-density tail lobes.” https://t.co/O218eVB2eK
“Solar wind pressure pulses are known to be associated with enhanced ionospheric Joule heating.” https://t.co/O218eVB2eK
“Furthermore, the ionospheric Joule heating is large both in the auroral oval region and in the polar cap, due to the very strong electric fields in the polar cap region.” https://t.co/O218eVB2eK
Magnetosphere electrons. “It is obvious that the strong activity drives highly enhanced auroral precipitation to a wide and expanded auroral oval.” https://t.co/O218eVB2eK
Two processes consume energy in the ionosphere: “Both quantities can be computed from the ionospheric solution of the global simulation.” https://t.co/O218eVB2eK
“Mainly two processes consume energy in the ionosphere: Joule heating resulting from the ionospheric closure of field-aligned currents and precipitation of magnetospheric electrons causing the auroral displays.” https://t.co/O218eVB2eK
“As all magnetospheric activity is powered by energy input from the solar wind, detailed understanding of the energy transfer processes and mechanisms is a key challenge for space weather applications.” https://t.co/O218eVB2eK
Magnetic sculpting. “The tail radius and flaring angle (deviation from a cylindrical shape) are to some extent controlled by the interplanetary magnetic field direction, which controls the intensity of reconnection at the nose of the magnetosphere.” https:
“The size is largely controlled by the solar wind dynamic pressure, which is balanced by the magnetic pressure inside the magnetosphere.” https://t.co/O218eVjrnc
“The size and shape of the magnetosphere is controlled by the interaction of the interplanetary magnetic field and solar wind flow with the internal geomagnetic field and the magnetospheric plasma environment.” https://t.co/O218eVjrnc
“To provide conceptual and predictive models of the magnetospheric evolution, large-scale global magnetohydrodynamic (MHD) simulations have been developed.” https://t.co/O218eVjrnc
“Even with neutral atom imaging, much of the magnetosphere remains invisible to our eyes and instrumentation.” https://t.co/O218eVjrnc
Magnetosphere. “However, the low signal to noise ratio and the complex inversion process from the line-of-sight measurements to spatially resolved ion distributions still limits the imaging applications.” https://t.co/O218eVjrnc
Ring currents. “As these are populations highly sensitive to processes occurring during space weather events, neutral atom imaging is becoming a new tool to monitor the state of the inner regions of the magnetosphere.” https://t.co/O218eVjrnc